Level 100 Hybrid MoM Rain of Arrows Inquisitor^3.21

Notes

Tree/build listed here is not to be used; just repurposed a PoB from something else with lots of mana regen to test numbers in.

Interesting build idea: mana stacker + Indigon + Battlemage's Cry + Manaforged Arrows + Bow attack skill -> scale bow attack mana cost for manaforged arrows buff and Indigon increased spell damage, which Battlemage's Cry converts back into
attack damage; Indigon ramps that mana cost higher, which ramps the spell damage increase and thus the Battlemage's Cry attack damage buff, while also increasing the manaforged arrows buff. Heavily depends on precise numbers:
the manaforged arrows buff perhaps most of all, but also bow attack mana costs and mana stacking and mana regen and so on.

Option 1:
Our Manaforged Arrows skill: Tornado Shot (Lv. 20 -> 10 mana) -> 130% (Elemental Damage with Attacks) -> 140% (Swift Affliction) -> 140% (Cruelty) -> 200% (Manaforged Arrows) -> 50 base mana cost
Our main Bow skill: Burning Arrow (Lv. 21 -> 13 mana) -> 140% (Swift Affliction) -> 140% (Cruelty) -> 130% (Elemental Damage with Attacks) -> 130% (Burning Damage) -> 110% (Additional Accuracy) -> 47 base mana cost
6 Burning Arrow attacks per 4 seconds (triggering 2 Tornado Shots) -> 47*6 + 50*2 = 382 mana cost per 4 seconds
This converges: approximately to 549 Mana, meaning total mana spent Recently is approximately 4392.
That gives us a 584 mana cost for our triggered Manaforged Arrows skill, which gives us a 584% More damage multiplier on Tornado Shot, which is reduced by 31% to 403% More damage (5.03x more damage).

Let's try to converge higher.
Option 2:
Our Manaforged Arrows skill: Same Tornado shot setup as before.
Our main Bow skill: Rain of Arrows (lv. 20 -> 10 mana) -> 140% (Deadly Ailments) -> 140% (Cruelty) -> 140% (Swift Affliction) -> 130% (Elemental Damage with Attacks) -> 140% (Concentrated Effect)
6 Rain of Arrows attacks per 4 seconds (triggering 2 Tornado Shots) -> 49*6 + 50*2 = 394 mana cost per 4 seconds
This converges: approximately to 1649 Mana, meaning total mana spent Recently is approximately 13192.
That gives us a 1701 mana cost of our Manaforged Arrows skill, which gives us a 1701% More damage multiplier on Tornado Shot, which is reduced by 31% to 1173% More damage (12.73x more damage).

Battlemage's Cry also gives us scaling Attack Damage from the increased Spell Damage given to us by Indigon.
Option 1: we're getting 525% increased Spell Damage, so depending on how much we invest into Battlemage's Cry warcry effect and power, we can get between 393% increased Attack Damage and 1100% increased Attack Damage.
Option 2: we're getting 1625% increased Spell Damage, so depending on how much we invest into Battlemage's Cry warcry effect and power, we can get between 1200% increased Attack Damage and 3400% increased Attack Damage.

So the overview: the skill gems and supports can be swapped as desired, so long as several constants remain the same: the base mana cost and the attacks per second.
If it says "140%" for a support gem, any 140% support gem can go there - doesn't matter which. Same for "base cost" skill - could be Rain of Arrows lv. 20 or Lightning Arrow lv. 20 or anything with that same cost.

Option 1 for lower mana regen costs: requires 1098 Mana regenerated per second, but gains you 5.03x More damage for the Manaforged Arrows skill and 1100% increased Attack Damage for both bow skills.
Option 2 for maximum power at the expense of the highest mana regen costs: requires 3298 Mana regenerated per second, but gains you 12.73x More damage for the Manaforged Arrows skill and 3400% increased Attack Damage for both bow skills.